opcodes/vax-dis.c

   1 /* Print VAX instructions.
   2    Copyright (C) 1995, 1998 Free Software Foundation, Inc.
   3    Contributed by Pauline Middelink <middelin@polyware.iaf.nl>
   4
   5 This program is free software; you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation; either version 2 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program; if not, write to the Free Software
  17 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  18
  19 #include "opcode/vax.h"
  20 #include "dis-asm.h"
  21
  22 /* Local function prototypes */
  23 static int
  24 print_insn_arg PARAMS ((const char *, unsigned char *, bfd_vma,
  25                         disassemble_info *));
  26
  27 static int
  28 print_insn_mode PARAMS ((int, unsigned char *, bfd_vma, disassemble_info *));
  29
  30 static char *reg_names[] =
  31 {
  32   "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
  33   "r8", "r9", "r10", "r11", "ap", "fp", "sp", "pc"
  34 };
  35
  36 /* Sign-extend an (unsigned char). */
  37 #if __STDC__ == 1
  38 #define COERCE_SIGNED_CHAR(ch) ((signed char)(ch))
  39 #else
  40 #define COERCE_SIGNED_CHAR(ch) ((int)(((ch) ^ 0x80) & 0xFF) - 128)
  41 #endif
  42
  43 /* Get a 1 byte signed integer.  */
  44 #define NEXTBYTE(p)  \
  45   (p += 1, FETCH_DATA (info, p), \
  46   COERCE_SIGNED_CHAR(p[-1]))
  47
  48 /* Get a 2 byte signed integer.  */
  49 #define COERCE16(x) ((int) (((x) ^ 0x8000) - 0x8000))
  50 #define NEXTWORD(p)  \
  51   (p += 2, FETCH_DATA (info, p), \
  52    COERCE16 ((p[-1] << 8) + p[-2]))
  53
  54 /* Get a 4 byte signed integer.  */
  55 #define COERCE32(x) ((int) (((x) ^ 0x80000000) - 0x80000000))
  56 #define NEXTLONG(p)  \
  57   (p += 4, FETCH_DATA (info, p), \
  58    (COERCE32 ((((((p[-1] << 8) + p[-2]) << 8) + p[-3]) << 8) + p[-4])))
  59
  60 /* Maximum length of an instruction.  */
  61 #define MAXLEN 25
  62
  63 #include <setjmp.h>
  64
  65 struct private
  66 {
  67   /* Points to first byte not fetched.  */
  68   bfd_byte *max_fetched;
  69   bfd_byte the_buffer[MAXLEN];
  70   bfd_vma insn_start;
  71   jmp_buf bailout;
  72 };
  73
  74 /* Make sure that bytes from INFO->PRIVATE_DATA->BUFFER (inclusive)
  75    to ADDR (exclusive) are valid.  Returns 1 for success, longjmps
  76    on error.  */
  77 #define FETCH_DATA(info, addr) \
  78   ((addr) <= ((struct private *)(info->private_data))->max_fetched \
  79    ? 1 : fetch_data ((info), (addr)))
  80
  81 static int
  82 fetch_data (info, addr)
  83      struct disassemble_info *info;
  84      bfd_byte *addr;
  85 {
  86   int status;
  87   struct private *priv = (struct private *) info->private_data;
  88   bfd_vma start = priv->insn_start + (priv->max_fetched - priv->the_buffer);
  89
  90   status = (*info->read_memory_func) (start,
  91                                       priv->max_fetched,
  92                                       addr - priv->max_fetched,
  93                                       info);
  94   if (status != 0)
  95     {
  96       (*info->memory_error_func) (status, start, info);
  97       longjmp (priv->bailout, 1);
  98     }
  99   else
 100     priv->max_fetched = addr;
 101
 102   return 1;
 103 }
 104
 105 /* Print the vax instruction at address MEMADDR in debugged memory,
 106    on INFO->STREAM.  Returns length of the instruction, in bytes.  */
 107
 108 int
 109 print_insn_vax (memaddr, info)
 110      bfd_vma memaddr;
 111      disassemble_info *info;
 112 {
 113   const struct vot *votp;
 114   const char *argp = NULL;
 115   unsigned char *arg;
 116   struct private priv;
 117   bfd_byte *buffer = priv.the_buffer;
 118
 119   info->private_data = (PTR) &priv;
 120   priv.max_fetched = priv.the_buffer;
 121   priv.insn_start = memaddr;
 122   if (setjmp (priv.bailout) != 0)
 123     {
 124       /* Error return.  */
 125       return -1;
 126     }
 127
 128   FETCH_DATA (info, buffer + 2);
 129   for (votp = &votstrs[0]; votp->name[0]; votp++)
 130     {
 131       register vax_opcodeT opcode = votp->detail.code;
 132
 133       /* 2 byte codes match 2 buffer pos. */
 134       if ((bfd_byte) opcode == buffer[0]
 135           && (opcode >> 8 == 0 || opcode >> 8 == buffer[1]))
 136         {
 137           argp = votp->detail.args;
 138           break;
 139         }
 140     }
 141   if (argp == NULL)
 142     {
 143       /* Handle undefined instructions. */
 144       (*info->fprintf_func) (info->stream, ".word 0x%x",
 145                              (buffer[0] << 8) + buffer[1]);
 146       return 2;
 147     }
 148
 149   /* Point at first byte of argument data, and at descriptor for first
 150      argument.  */
 151   arg = buffer + ((votp->detail.code >> 8) ? 2 : 1);
 152
 153   /* Make sure we have it in mem */
 154   FETCH_DATA (info, arg);
 155
 156   (*info->fprintf_func) (info->stream, "%s", votp->name);
 157   if (*argp)
 158     (*info->fprintf_func) (info->stream, " ");
 159
 160   while (*argp)
 161     {
 162       arg += print_insn_arg (argp, arg, memaddr + arg - buffer, info);
 163       argp += 2;
 164       if (*argp)
 165         (*info->fprintf_func) (info->stream, ",");
 166     }
 167
 168   return arg - buffer;
 169 }
 170
 171 /* Returns number of bytes "eaten" by the operand, or return -1 if an
 172    invalid operand was found, or -2 if an opcode tabel error was
 173    found. */
 174
 175 static int
 176 print_insn_arg (d, p0, addr, info)
 177      const char *d;
 178      unsigned char *p0;
 179      bfd_vma addr;              /* PC for this arg to be relative to */
 180      disassemble_info *info;
 181 {
 182   int arg_len;
 183
 184   /* check validity of addressing length */
 185   switch (d[1])
 186     {
 187     case 'b' : arg_len = 1;     break;
 188     case 'd' : arg_len = 8;     break;
 189     case 'f' : arg_len = 4;     break;
 190     case 'g' : arg_len = 8;     break;
 191     case 'h' : arg_len = 16;    break;
 192     case 'l' : arg_len = 4;     break;
 193     case 'o' : arg_len = 16;    break;
 194     case 'w' : arg_len = 2;     break;
 195     case 'q' : arg_len = 8;     break;
 196     default  : abort();
 197     }
 198
 199   /* branches have no mode byte */
 200   if (d[0] == 'b')
 201     {
 202       unsigned char *p = p0;
 203
 204       if (arg_len == 1)
 205         (*info->print_address_func) (addr + 1 + NEXTBYTE (p), info);
 206       else
 207         (*info->print_address_func) (addr + 2 + NEXTWORD (p), info);
 208
 209       return p - p0;
 210     }
 211
 212   return print_insn_mode (arg_len, p0, addr, info);
 213 }
 214
 215 static int
 216 print_insn_mode (size, p0, addr, info)
 217      int size;
 218      unsigned char *p0;
 219      bfd_vma addr;              /* PC for this arg to be relative to */
 220      disassemble_info *info;
 221 {
 222   unsigned char *p = p0;
 223   unsigned char mode, reg;
 224
 225   /* fetch and interpret mode byte */
 226   mode = (unsigned char) NEXTBYTE (p);
 227   reg = mode & 0xF;
 228   switch (mode & 0xF0)
 229     {
 230     case 0x00:
 231     case 0x10:
 232     case 0x20:
 233     case 0x30: /* literal mode                  $number */
 234       (*info->fprintf_func) (info->stream, "$0x%x", mode);
 235       break;
 236     case 0x40: /* index:                        base-addr[Rn] */
 237       p += print_insn_mode (size, p0 + 1, addr + 1, info);
 238       (*info->fprintf_func) (info->stream, "[%s]", reg_names[reg]);
 239       break;
 240     case 0x50: /* register:                     Rn */
 241       (*info->fprintf_func) (info->stream, "%s", reg_names[reg]);
 242       break;
 243     case 0x60: /* register deferred:            (Rn) */
 244       (*info->fprintf_func) (info->stream, "(%s)", reg_names[reg]);
 245       break;
 246     case 0x70: /* autodecrement:                -(Rn) */
 247       (*info->fprintf_func) (info->stream, "-(%s)", reg_names[reg]);
 248       break;
 249     case 0x80: /* autoincrement:                (Rn)+ */
 250       if (reg == 0xF)
 251         {       /* immediate? */
 252           int i;
 253
 254           FETCH_DATA (info, p + size);
 255           (*info->fprintf_func) (info->stream, "$0x");
 256           for (i = 0; i < size; i++)
 257             (*info->fprintf_func) (info->stream, "%02x", p[size - i - 1]);
 258           p += size;
 259         }
 260       else
 261         (*info->fprintf_func) (info->stream, "(%s)+", reg_names[reg]);
 262       break;
 263     case 0x90: /* autoincrement deferred:       @(Rn)+ */
 264       if (reg == 0xF)
 265         (*info->fprintf_func) (info->stream, "*0x%x", NEXTLONG (p));
 266       else
 267         (*info->fprintf_func) (info->stream, "@(%s)+", reg_names[reg]);
 268       break;
 269     case 0xB0: /* displacement byte deferred:   *displ(Rn) */
 270       (*info->fprintf_func) (info->stream, "*");
 271     case 0xA0: /* displacement byte:            displ(Rn) */
 272       if (reg == 0xF)
 273         (*info->print_address_func) (addr + 2 + NEXTBYTE (p), info);
 274       else
 275         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTBYTE (p),
 276                                reg_names[reg]);
 277       break;
 278     case 0xD0: /* displacement word deferred:   *displ(Rn) */
 279       (*info->fprintf_func) (info->stream, "*");
 280     case 0xC0: /* displacement word:            displ(Rn) */
 281       if (reg == 0xF)
 282         (*info->print_address_func) (addr + 3 + NEXTWORD (p), info);
 283       else
 284         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTWORD (p),
 285                                reg_names[reg]);
 286       break;
 287     case 0xF0: /* displacement long deferred:   *displ(Rn) */
 288       (*info->fprintf_func) (info->stream, "*");
 289     case 0xE0: /* displacement long:            displ(Rn) */
 290       if (reg == 0xF)
 291         (*info->print_address_func) (addr + 5 + NEXTLONG (p), info);
 292       else
 293         (*info->fprintf_func) (info->stream, "0x%x(%s)", NEXTLONG (p),
 294                                reg_names[reg]);
 295       break;
 296     }
 297
 298   return p - p0;
 299 }